Nanoscale Spectroscopy and Imaging of Single Epitaxial GaAs Nanocrystals

Abstract

In this paper, we present a study of structural and optical properties of single faceted dome-like GaAs nanocrystals (NCs) and planar nanowires (NWs) obtained by self-catalytic growth on Si (111) substrates and GaAs (001), respectively. Their structural properties were characterized using atomic-force and scanning electron microscopies. Tip-enhanced photoluminescence (TEPL) from single faceted GaAs NCs was observed allowing TEPL imaging with a spatial resolution of 20 nm. The interaction of the Au tip with GaAs NCs and NWs induces plasmon-enhanced emission enabling the nanoscale imaging of single GaAs nanostructures. Tip-enhanced Raman scattering by a vibrational mode from As clusters was observed and the local distribution of As clusters on a single GaAs NW was established.